The present invention relates to a refractory metal core for use in a casting system.
Refractory metal cores (RMCs) are metal based casting cores usually composed of molybdenum with a protective coating. The refractory metal provides more ductility than conventional ceramic core materials while the coating (usually ceramic) protects the refractory metal from oxidation during the shell fire step of the investment casting process and prevents dissolution of the core from molten metal. RMCs have shown significant promise in casting feature sizes and geometries not attainable with ceramic cores.
One method of using refractory metal cores is shown in U.S. Published Patent Application No. 2003/0075300, entitled “CORES FOR USE IN PRECISION INVESTMENT CASTING”, to Shah et al., which is hereby incorporated by reference herein.
Currently, many gas path component designs are being considered that use a refractory metal core in conjunction with a ceramic core. The ceramic core has many benefits that favor its use in larger sections. Typically, the refractory metal has attached to the ceramic core and have been employed for small feature sizes and complex geometry due to its increased ductility.
Blade outer air seals (BOAS) and low pressure turbine (LPT) blades are two components that may not require large cooled sections but could benefit from either improved cooling or lower cost potential afforded by RMC technology.